As a CG artist, familiarity with the character-creation process is crucial. This chapter teaches you how to set up a modeling session, bring in designs as image planes, create symmetrical low-polygon geometry, extrude and move edges, and get the character ready for skinning.

Nearly all modern visual-effects-laden films and shows contain at least some character animation. From talking fuzzy animals to drooling insects, the television and film VFX markets rely heavily on modelers who can bring designs to life in 3D. This means that for your purposes as a CG artist, familiarity with the character-creation process is crucial. If you are planning on moving further down the character-modeling path, this Hour will be helpful for you to start getting accustomed to common considerations with CG character models.

NOTE

Working A-Head

We will go over common issues in character modeling that cover both the head and the body, although there are enough issues to discuss about head and face modeling to fill an entire book. Remember to use the concepts and exercises in this book as a jumping-off point for further study in CG and in Maya.

In this Hour, you will encounter the most common issues surrounding character modeling and learn how to overcome them. You will set up a scene in a way that allows for easy character creation and accurate modeling from a design. You will also learn about modeling considerations as they pertain to a production. Like most of the CG disciplines, character modeling is subject to personal workflows. Therefore, as you read this Hour, take note of the concepts that seem to come naturally to you, and those that are a little more difficult, so that in your personal exercises later on you can focus on finding your own way to achieve the goals explained here.

Character Model Basics

With a little bit of polygon modeling experience, you can pretty much intuit the process of creating a character model. The literal acts of extruding, adding edge loops, and merging vertices are all the same when you are modeling a character as when you are modeling a cell phone or a car. However, because characters are almost always meant to deform and move onscreen, certain important considerations must be made to ensure successful character modeling.

Working From Designs

One of the first considerations you have to make is whether you are going to be working from drawn character designs. If so, it is imperative that you have those drawings imported and arranged in your scene in a way that helps you get the 3D model as accurate as possible. Because it is common to work from designs, Maya makes it easy to get your images into the scene. Figure 8.1 shows how close to a design it is possible to create a character.

FIGURE 8.1. This finished character model looks very close to the design because we were careful to use all of Maya’s available tools.

To begin, we must first create planes that will serve as guides in 3D space as to where our geometry is supposed to be placed. This is commonly achieved in one of two ways: using camera image planes or using polygonal planes with the designs as a texture. The first way involves importing the image as a background in your panel—otherwise known as an “image plane” (more in Hour 22, “Working with Film”). The advantages to this method are that Maya automatically retains the aspect ratio of your drawing, so an extra step is removed. The downside is that to move, rotate, or scale these planes, you must do so through the image plane’s attributes in the Attribute Editor, which can be cumbersome when you are in the middle of modeling the character. Even with this drawback, the camera image planes are quicker and easier to create than polygonal planes, so we will use them.

First, we must locate our designs and make sure they have been created correctly. We just need to make sure that the front and side views’ images line up perfectly. Navigate to this Hour’s source files directory and open up design_Ortho.jpg (see Figure 8.2).

FIGURE 8.2. Notice how this design was created with the character perfectly lined up in both the front and side views. This makes it so that we have the most accurate guide and the easiest time matching the design.

You can clearly see that the front and side views line up correctly. So in order to use these designs, we must load them as image planes on their respective cameras. Open Maya, and in any panel, go to Layouts, Saved Layouts, Four Panes. This will reset your panel layout to the well-known standard layout shown in Figure 8.3.

Next, we load the images as the image planes for the front and side cameras. In the front panel, go to View, Image Plane, Import Image.... Navigate to this Hour’s source files and choose image_Front.jpg. The image has been cropped for the front view. In the Attribute Editor (which should open automatically when you create the image plane), one of the very first sliders is the Alpha Gain. This controls how “see-through” your image planes are. Set the Alpha Gain to .5 for the front image plane as well as the side image plane when you are done importing it. The properly loaded image is shown in Figure 8.4.

FIGURE 8.4. The front view of the design loaded as an image plane into the front panel. The alpha gain (circled) is set to .5. Notice also that transparency is working correctly in the Persp panel with Viewport 2.0 set as our renderer.

NOTE

Viewport 2.0

We are going to set our Persp panel to render with Viewport 2.0. This panel render engine has some quality features that give us great options for viewing models really beautifully in panel (even before rendering). In this case, however, we need Viewport 2.0 simply for the fact that it renders transparent image planes in the Perspective cameras correctly. In the Persp panel, go to Renderer, Viewport 2.0.

Now do the same for the side panel. Go to View, Image Plane, Import Image... one more time and find the image_Side.jpg file. Once it is loaded, you can see in the Persp panel that both images are placed at the world origin, ready for your use, as shown in Figure 8.5.

FIGURE 8.5. The two image planes loaded into Maya. Notice how they maintain their aspect ratio by default, which is an extra step you have to take care of if you were to create polygon planes and arrange them yourself in this manner.

We will want to move the image planes so they are not in the way of the character when we start to model him. Select the front image plane and press Ctrl+A to bring up the Attribute Editor. If you scroll down the attributes, you will see a section called Placement Extras. You can resize your image plane and move it around the scene using these attributes. The Image Center attribute controls where the plane is placed. We want to move the image plane backward so it will be behind the model, so change the value in the far-right box next to Image Center (this is the Z value, even though it is not labeled) to –8. Select the side image plane and make the X value (first box) in its Image Center attribute –12. Figure 8.6 shows the planes with their correct positions.

FIGURE 8.6. The image planes as they should be, lined up and ready to guide us as we create our geometry.

TIP

Seeing Three Boxes? It’s XYZ!

Any time Maya has three inputs or attributes next to each other with no labeling, it is assumed that the three attributes control the X, Y, and Z values of whatever node you are editing. Be warned, though: Sometimes direction is relative, like in the sense of the Front and Side cameras, where Z is always away from camera, and might not line up with the Z axis in world space.

Once that is completed, we are almost ready to start creating geometry the same way we did with the hammer in Hour 4, “Modeling with Polygonal Geometry.” There are just a few more steps to take to make sure we are going to have the most efficient workflow when modeling. Create a polygon sphere by going to Create, Polygons, Sphere. Click anywhere in the front panel and press the 5 key to shade the objects. As you can see, the sphere is opaque and we cannot see our image planes through it. To see through objects in a panel, click on (in your panel) Shading, X-ray. RMB drag on the sphere and choose vertex. With the vertices highlighted, it’s easy to see how intuitive and simple it will be to line up the polygons with details in the designs.

NOTE

Image Specifics

The importance of having accurate, well-drawn orthographic images cannot be overstated. If you try to use this method of creating image planes with designs that were not drawn from straight-on and side angles, your results will be highly skewed. It is also imperative that the images share at least one of the same dimensions—be it width or height—so that scaling the images (using the Width and Height attributes) can be done uniformly. The best practice is to combine the two images into one image to line them up, and then crop and save the two views out separately, retaining the image size.

Using Symmetry In Modeling

We’re nearly ready to start modeling. Before we begin, we need to set up our model so that when we work on one side of the character, the other side will update as well. There are a wide variety of ways to do this, so I will show you the way that works the simplest—a “mirrored instance.”

NOTE

Duplicates and Instances

The main difference between duplicating an object and instancing an object is that the instance will continue to update with modifications until it is converted into a separate object. Think about an instance as a duplicate with a continuous link to the other object, always updating and adjusting as you work. This link even persists if you delete history on both objects.

To create a mirrored instance, we are going to start with a single polygon. Create a polygon plane by clicking Create, Polygon Primitives, Plane and then the options box [wr]. In the options box that appears, make sure the width divisions and height divisions are both set to 1 and then click Create. Now in the Persp panel, RMB drag and select the two vertices on the left side of the side image plane (the two vertices in negative X space) so that you can move them to the axis, as in Figure 8.7.

FIGURE 8.7. The newly created polygon plane, with the two vertices selected.

We are going to move these two vertices to the center of the world axis. Press W to switch to the Move tool. Now, holding down the X key makes it so that Maya will snap a vertex to the gridlines (the V key snaps to vertices, and the C key snaps to curves). With the X key pressed, move these two vertices along the X axis until they snap to the center (they will be aligned with the side panel’s image plane). Figure 8.8 shows the vertices in the correct position.

Now we will instance this geometry. Press F8 to return to object mode or RMB drag on the plane and choose “object.” Go to Edit, Duplicate Special and then the options box [wr]. In the options box, change “Geometry type” to “Instance,” and in the first value box (the X value) for “Scale,” enter –1 (remember that when you see three boxes, they are X, Y, and Z). Leave the rest of the settings at default and hit “Duplicate Special”. A new plane will mirror across the X axis (the result of scaling it by –1), and it is an instance of our first plane. The two planes are now linked together, as shown in Figure 8.9, and all of the edits and modifications you do to the geometry of one will be applied to both simultaneously.

FIGURE 8.9. The final result of mirrored instancing. The two planes are instanced objects; therefore, when we make adjustments, and even add geometry onto these objects, they will give us a symmetrical model.

NOTE

Negative Transforms and Normals

Remember normals? They were mentioned in the Hour 4 quiz, and are basically the “direction” that Maya considers a polygon to be “facing.” If you perform a Modify, Freeze Transformations on a piece of geometry with negative scale, it will flip the normal so that the surface is facing inward. This is a problem for UV’ing and rendering, and even some other effects that rely on face normals. Do not Freeze Transformations on a piece of mirrored geometry; we will perform the necessary steps to make sure we can combine the instanced objects correctly.